Liquid storage tank



June 28, 1960 w. c. KLANK, JR 2,942,612

LIQUID STORAGE TANK Filed May 21, 1959 ma/0 our 5 INV ENT OR. wm 75@ c#Mw/q me United States Patent LIQUID STORAGE TANK Walter C. Klank, Jr.,Dayton, Ohio, assignor to United Aircraft Products, Inc., Dayton, Ohio,a corporation of Ohio Filed May 21, 1959, Ser. No. 814,885

6 Claims. (Cl. 137-43) This invention relates to tanks storing a liquidand useful in vehicles such as aircraft wherein the tank assumes varyingattitudes relative to the earths surface in correspondence with themovements of the aircraft. While not so limited, the invention hasespecial applica- .tion to oil supply systems in aircraft wherein an oilis taken from the tank to a place of use and then returned to the tankfor storage and subsequent reuse.

In tanks and systems as described, the oil returning to the tank isaccompanied by relatively large amounts of air. lt is a design objectiveto provide for the rapid and eicient release of such air from the tank.

A general object of the invention is to provide a new vent system in atank as described particularly characterized by means restricting theescape of liquid from the tank by way of the vent system in and duringmovement to changing tank attitudes, including a roll.

Another object of the invention is to present a new vent valve for usein tanks as described characterized by means restricting an escape ofliquid through the vent system not only in inverted flight and underconditions of negative gravity but also in a -roll attitude ofpredetermined direction and extent.

Other objects and structural details of the invention will appear fromthe following description when read in connection with the accompanyingdrawings, wherein:

Fig. l is a diagram of a tank having a vent system in accordance withthe illustrated embodiment of the invention;

Fig. 2 is a View, partly diagrammatic, showing a dual valve comprised inthe vent system as itV appears in a level flight attitude;

Fig. 3 is a view like Fig. 2 showing the valve as it appears in a 90roll flight attitude, the roll being in a counterclockwise directionfrom level attitude;

Fig. 4 is a View like Figs. 2 and 3 showing the valve as it appearsunder conditions of, negative gravity, the valve also assuming thisposition in inverted ight; and

Fig. 5 is a view like Figs. 2 to 4 showing the valve as it appears in aclockwise direction 90 roll.

Referring to the drawings, the tank and the liquid and vent systemsassociated therewith area shown in the main in diagrammatic form, theinvention having particular reference as noted to a dual valveYmechanism in the vent system and to the manner in which such valveatects venting in the tank.

Thus, a liquid storage tank in accordance with the illustratedembodiment of the invention comprises a tank shell having a liquid inlet11, a liquid outlet 12 and a vent or air outlet 13. The liquid inlet is,in tanks of the present class, selectively located and arranged incooperation with other elements of the tank to admit the returningliquid to the tank in a manner to promote the release of entrained airand to avoid turbulence. In the present instance, the lreturning liquidis admitted to the lower end of a compartment 14 within the tank. The

mixture of liquid and air rises in the compartment 14 andl spills outover the open upper end thereof, the period of containment within thecompartment providing a dwell period in which the air tends effectivelyto separate from the liquid. Upon discharge over the upper end of thecompartment, therefore, the liquid spills over the upper edge into themain body of contained liquid while the air continues to rise, movinginto the upper part of the tank above the liquid level. The liquidoutlet 12 may be suitably located -for discharge of the liquid and insome instances is associated with means to insure a continuing supply ofliquid in dierent flight attitudes. In the present instance the locationof the outlet 12 is in what may be considered to be the normal lowerportion of the tank in that its location is at the bottom of the tankwhen the tank is in a normal, level, ight attitude. It is thuscontinuously supplied with liquid in most flight attitudes.

The vent outlet 13 is in the normal upper portion of the tank, havingregard to normal flight attitudes. The outlet 13 is a part of a Ventsystem further including a chamber 15 which communicates with the outlet13 and is defined by a wall 16 serving essentially to exclude thechamber 15 from communication with the main interior of the tank 10.Communicating freely with the vent chamber 15 is one end of a tube 17extending toward the lower part of the tank shell and communicatingtherewith at its opposite end. Other tubes 1S and 19 are disposed withinthe vent chamber 15 and have Itheir one ends opening through the wall 16to comunicate with the interior of the tank in the upper portion thereofat opposite ends of the vent chamber, as indicated. At their oppositeends the tubes A18 and 19 communicate with the interior of the ventchamber 15 through a valve 21 in a manner to be more particularlydescribed. The several tubes 17, 18 and 19 are formed in circuitousfashion to obviate the entrapment of liquid therein as the tank movesfrom one attitude to another and the consequent slugging or discharge ofthe trapped oil into the vent chamber 15. Such liquid as may be admittedto the vent chamber may escape therefrom, however, by way of the tube 17when the tank returns to a normal flight attitude. The ventingarrangement, it will be understood, is one to vent the interior of thetank in varying tank attitudes and under Varying conditions. The tubes18 and 19 vent the upper portion of the tank continuously in normalHight attitudes and in longitudinally tilted positions corresponding toclimbing and diving attitudes. Tube 17 Vents the tank under invertedight conditions and inverted like conditions wherein the containedliquid moves to the normal upper part of the tank in response to theapplication of negative gravity forces, or to inverted ilight.

Referring now to Figs. 2 to 5, the valve 21 includes a fabricated body22 wherein a transverse partition 23 divides the interior of the bodyessentially into compartments 24 and 25. In what may be considered to bethe upper surface of the body 22 is an opening 26 cornmunicating thecompartment 25 with the chamberV 15. The sides of the valve body areadapted, in a manner not fully shown herein, to receive the adjacentends ofl the tubes 18 and 19, the latter being disposed to communicatewith body chamber 24. An opening 27 in the partition wall 23intercommunicates the compartments 24 and 25. Within the compartment 24is a frusto-conical cage 28, the frustrum thereof terminating in thewall23 in surrounding relation to the opening 27. There is similarlyprovided in the compartment 25 a frustoconical cage 29 terminating atits frustrum in the upper wall of body 22 in surrounding relation to theopening 26. The arrangement is one to place the cages 2S and 29 at rightangles to one another. flight attitude, illustrated in Fig. 2, the cage28 is hori- In a normal, level` zontally disposed While the cage 29 isvertically disposed. Within the cages are respective freely rollingballs 31 and 32 of a size to seat in and close the respective openings27'and 26. t

As shown in Fig. 2, in anormal flight attitude the balls 31 and 32botlroccupy positions removed from the openings 26 and 27. Ball 32,under the inuence of gravity, lies in the bottom or base of the cage 29.Ball- 31, underY the combined influences of gravity and the inclinationof the side wall Vof cage 28, Vlies also at the bottom of the cage andin a position of rest on the side wall thereof. Under these conditions,therefore, a free movement of air from the tubes 18 and 19 to the ventchamber by way of compartment 24, opening 27, compartment 25 and opening26 is permitted. In the event of aV 90"V roll to the left or in acounter-clockwise direction, however, the ball Sp1-rides up the wall ofthe cage 28 and comes to rest Within the opening 27, effectivelyclosingsuch opening. The compartment-24 is thereby cut off from communicationwith the compartment 25 so that the tubes 18 and 19 are disconnectedfrom the vent chamber 15. LiquidV which might enter Vthe-vent chamber-under these conditions by virtue of flooding of the outer open ends ofthe tubes 18 and 19 accordingly is denied entrance. Ba1l32 remains inthe bottom of the cage resting against one side wall thereof.

Fig. 4 illustrates ,the position of the balls 31 and 32 underV theiniluence of negative gravity forces or in an inverted ight attitude.Under the conditions then applyingY the ball 32 moves to the fmstrum ofthe cage 29 Yand seatsin opening 26. Communication of the tubes 18 and19 with the vent chamber 15 thus is precluded as in tlierollV attitudeof Fig.v 3. Fig. 5 illustrates the 90 rollin the opposite directionwherein as seen no interruption of communication between the tubes 18and 19 and the vent chamber 15 is contemplated. It will be understood,however, thatY communication could Vunder these conditions bediscontinued also ify desired, as by interposing between the cages 28and 29 a further cage and ball, the cage being aligned with the cage 28but inversely arranged. t 'p Figs. 2 through 5 are, as herefore noted,partly diagrammatic. The diagrammatic manner of execution is directedVprimarily toward a clear showing of the manp ner in Ywhich compartment2'4 of valve assembly 2 1 communicates with Vadjacent ends of pipes 18and 19. Y True vertical longitudinal sections through-the valve assemblywould remove one of thepipes-18 or 19 from view entirely and ywouldpartly obscure therother by reason of the presence of Aball' 31.Accordingly, for purposes Y ofl clarity and simplicity, in Figs. 2through 5 the pipes to pass admitted air out of the tank from the normalupper portion thereof; and a pair of normally open gravity operatedvalves in said vent line, one closing said Yline under conditions ofinverted tankattitude and under conditions of negative gravity,`and theother closing said line under conditions'ofv a roll attitude ofpredetermined direction and extent. f

2.*A liquid storage'tank'which in-use assumes diifer-V ent attitudesvrelative to the earths surface and which includes outlet and inletconnections, the latter admitting-to the tank a liquid-airmixturegfincluding a vent linelto pass admitted Vair out of `the Vtankfrom the normal upper Vportion thereof; and alpair of normally openunder conditions of negative gravity,fand the other closing said lineunder conditions of a roll attitude of predetermined direction andextent.

3. A liquid storage tank which in use assumes diterent attitudesrelative to the earths surface and which includes outlet and inletAqnuections, the latter admitting to the tank a liquid-air mixture;including a vent chamber in said tank communicatingY with the tankexteriorgpvent tubes communicatingat their one ends with differentportions ofthe tank interior and'cterminating at their opposite endsl insaid vent chamber, atleast one of said vent tubes communicating at itssaid one end with the normal .upper portion o f the tank interior; andvalve means controlling the communication of said one Vtube with saidvent chamber, said means closing said tube from communication with thevent chamber under conditions ofl inverted tank attitude 'and underconditions of negative gravity vand also under conditions of a. rollattitudeV of Ypredetermineddirection and extent, said valve meanscomprising a'pair of independently .operable series arranged valves,hone responding to negative gravity forces and toY movement of the tankto inverted attitude and the other responding to a tank roll.

4. A liquid storage tank which in use assumes different attitudesrelative to the earths surface and which includes outlet and inletconnections, thel latter admitting Y to the tank a liquid-air mixture;including `a vent cham- Y ber in said tank communicating with the'tankexterior;

" per portion of the tank interioryand gravity operated gravity operatedvalves in said vent line, one closing f said line under conditions ofinverted, tank attitude and valve means controlling the communication ofsaid one tube with saidrventpchamber, said valve means including a bodyproviding. aV first Vcompartment communicat-Y ing with said vent chamberand a second compartment communicating with the said opposite end ofsaid one tube and with said rst compartment, a gravity responsive valvein said rst compartmentrmov'abl'e Yto interrupt venting from said firstcompartment Yto said vent chamber in response ,to` negative 'gravityforces and to inversionrof the valve body, and a gravity responsivevalve Vin said second' compartment movable to interrupt communicationbetweensaidsecond compartment and said first compartment in Vresponse toa rolling motionv of predetermined direction and extent of said body.

S. A'Vliquid storage tank which in use `assumes, diierentV attitudesrelative to the earths surface and which includes outlet andinletconnections, thelatter admittingv to theV tank a liquid and largeamounts of air; including a vent chamber in said' tank communicatingwith thetankext'erior; lvent tubes reaching at theirone' ends intoopposite ends of the tankin the` normal .upper portion thereof to ventsaid upper portion inr normal and forward and rearward tilted attitudesof the tank, the opposite ends of said tubes terminating in said ventchamber, a valve Y body through which said.. opposite ends of said tubescommunicate with-said vent chamber, said valve body providing a firstcompartment communicating with Vsaid tubes ,and a second compartmentYcommunicating with the-vent chamber and an opening intercommunicatingsaid rst and second compartments, a freely rolling `ball in said firstcompartment movable in response to a lateral tilt or roll of `the tankof a'predetermined extent in one direction to close said openingintercommunicating said rst and second compartments, and another ballfreely rolling'in said second chamber ,and movable toclose said secondcompartment from V,con'nnunication with saidyent chamber Vunder theinfluence ofrnegative gravity forces and in response toA inversionV ofthe tank. p Y Y t 6. A liquid storage tank according toV laim 5,characten'zed'inthat said first Ycompartment. of .said .valve bodyisforrmed with inclined walls to causesaid ball therein References Citedin the le of this patent UNITED STATES PATENTS Flanders Apr. 25, 1916Zoder Mar. 19, 1940 Gregory Mar. 7, 1944 Stewart Dec. 18, 1956 CarrollJuly 30, 1957 Eshbaugh Feb. 24, 1959 Simcock June 9, 1959

